Hi Sakari, On Sunday 01 May 2016 17:08:31 Sakari Ailus wrote: > On Sat, Apr 30, 2016 at 12:13:59AM +0200, Pavel Machek wrote: > > Hi! > > > > What is reasonable camera application for testing? > > > > N900 looks like a low-end digital camera. I have now have the hardware > > working (can set focus to X cm using command line), but that's not > > going to be useful for taking photos. > > I guess you already knew about omap3camd; it's proprietary but from purely > practical point of view it'd be an option to support taking photos on the > N900. That would not be extensible any way, the best possible functionality > is limited what the daemon implements. > > I'm just mentioning the option of implementing wrapper for the omap3camd so > that it can work with upsteam APIs, I don't propose that however. > > > In particular, who is going to do computation neccessary for > > autofocus, whitebalance and exposure/gain? > > I think libv4l itself has algorithms to control at least some of these. It > relies on the image data so the CPU time consumption will be high. > > AFAIR Laurent has also worked on implementing some algorithms that use the > histogram and some of the statistics. Add him to cc list. http://git.ideasonboard.org/omap3-isp-live.git That's outdated and might not run or compile anymore. The code is more of a proof of concept implementation, but it could be used as a starting point. With an infinite amount of free time I'd love to work on an open-source project for computational cameras, integrating it with libv4l. > > There's http://fcam.garage.maemo.org/gettingStarted.html that should > > work on maemo, but a) it is not in Debian, b) it has non-trivial > > dependencies and c) will be a lot of fun to get working... > > (and d), will not be too useful, anyway, due to 1sec shutter lag: > > I believe this will be shorter nowadays. I don't remember the exact > technical solution which the text below refers to but I'm pretty sure it'll > be better with the current upstream. API-wise, there's work to be done there > (to port FCAM to upsteram APIs) but it's a possibility. > > > Fast resolution switching (less shutter lag) > > FCam is built on top of V4L2, which doesn't handle rapidly varying > > resolutions. When a Shot with a different resolution to the previous > > one comes down the pipeline, FCam currently flushes the entire V4L2 > > pipeline, shuts down and restarts the whole camera subsystem, then > > starts streaming at the new resolution. This takes a long time (nearly > > a second), and is the cause of the horrible shutter lag on the N900. A > > brave kernel hacker may be able to reduce this time by fiddling with > > the FCam ISP kernel modules and the guts of the FCam library source > > (primarily Daemon.cpp). > > Anyone who solves this one will have our undying gratitude. An ideal > > solution would be able to insert a 5MP capture into a stream of > > 640x480 frames running at 30fps, without skipping more than the frame > > time of the 5MP capture. That is, the viewfinder would effectively > > stay live while taking a photograph. > > > > ) > > > > Any other application I should look at? Thanks, -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
